Is it ok to use an asymmetric split supply for AVdd and AVss? I would like to measure a unipolar signal with AIN- that is slightly below ground (about -200 mV at most). To maximize the resolution of my external 2.5 volt reference I would like to reference it to ground and then set AVss to -1V and AVdd to 2.6V. I've tried out this setup in the virtual eval tool and it doesn't complain but I wanted to make sure this is a valid setup because the datasheet only talks about a symmetrical split supply of +/- 1.8V.
If there is a better solution to reading slightly negative voltages that doesn't require numerous external components I would be open to that as well. The reason the voltage AIN- is slightly negative sometimes is that I'm measuring the output of multiple high current power supplies deferentially and the ADC ground is slightly up stream of the power supply return connection. Keeping the ADC ground at the same potential as the power supply return might be possible but would complicate the wiring harness which I would like to avoid.
